Nice seats but none really resemble a GT40 seat. In the book by JS Allen, (car 1032 on page 58)it shows how utility the seats can be in a typical racing car. That doesn't mean to say that we need to conform 'downwards'. Have another look on page 35 (GT/108) - another example.
Incidently seats in early cars were dark blue and later cars black.
As an aside, on page 60 in the same book on page 60 is a chassis outside John Etheridge's works. Somebody , probably in the USA, is making chassis almost identical to the one in the picture but I can't find out where - anybody know.
Dave.